METHOD FOR PREPARING ACETIC ACID Russian patent published in 2008 - IPC C07C53/08 C07C51/12 

FIELD: chemical technology.

SUBSTANCE: invention relates to technology for synthesis of acetic acid by carbonylation of methanol. Method for synthesis of acetic acid is carried out by the carbonylation reaction of methanol and/or its reactive derivative in one or some reactors in the liquid reactive composition comprising iridium catalyst for the carbonylation reaction, ruthenium promoter, methyl iodide co-catalyst, methyl acetate, acetic acid and water. Liquid reactive composition from one or some reactors is fed for one or some separation steps by a single equilibrium evaporation to yield (I) vapor fraction containing component able to condensing and exhausting gas of low pressure containing carbon monoxide, and (II) liquid fraction containing iridium catalyst for the carbonylation reaction, ruthenium promoter and acetic acid as a solvent. Components able for condensing are isolated from exhausting gas of low pressure. The concentration of carbon monoxide in exhausting gas is maintained according to the formula: Y > mX + C wherein Y means the molar concentration of carbon monoxide in exhausting gas of low pressure; X means the concentration of ruthenium in the liquid reactive composition as ppm; m means about 0.012, and C means about -8.7. The concentration of carbon monoxide in exhausting gas of low pressure is in the range from 55 to 65 mole%, and the concentration of ruthenium in the liquid reactive composition is up to 5500 ppm. Method provides decreasing loss of the catalyst components at step for isolation of acetic acid based on enhancing stability of the catalytic system.

EFFECT: improved method of synthesis.

29 cl, 6 tbl, 2 dwg, 34 ex